The present invention relates to a steering device, particularly for marine outboard engines, which outboard engines have a clamping and/or gripping end for fastening them to the transom of a watercraft on which the motor and propeller assembly is mounted in such a manner as to rotate about a substantially vertical steering axis, and which steering device includes a closed hydraulic circuit having at least one pump driven by steering means, such as a steering wheel, a helm or the like and at least one double-acting cylinder which is slideably fitted on at least one coaxial rod, which rod sealingly projects out of a cylinder head and carries a separating piston which divides the cylinder into two variable volume chambers, each of which chambers has a hydraulic fluid inlet/outlet, each being connected to one of two inlets/outlets of the pump and with sealing heads for the mutually sliding cylinder and rod which are made of one piece with the cylinder, to at least one plate or bracket for securing the cylinder and rod assembly to the transom and/or to the end for fastening the motor to the transom, the bracket being non slideably attached to the at least one rod, at least one idler arm between the cylinder and outboard motor steering connection means which are integral with the motor.
Such devices are well known in the art and widely used. While these devices satisfactorily serve their function, they still suffer from certain drawbacks.
First, in these known devices, the rod is secured to the transom, whereas the cylinder slides along the rod. At its two opposite ends, the cylinder has one inlet/outlet respectively for feeding and discharging a fluid, typically oil, from each of the two piston-separated chambers. Since the cylinder moves along the rod, such connection shall be provided for each inlet and outlet by hoses, interposed between one end of each fluid feed conduit for each corresponding chamber and the corresponding chamber itself. Due to the rigidity required of the hoses, the continuous sliding motion of the cylinder causes their material to be stressed and possibly broken with time, especially in the portions extending from the transom to the cylinder fittings.
Further drawbacks in prior art devices are also associated to the way the rod is fastened to the stationary portion of the transom and/or to the clamp to be fastened to said transom of the motor. Here, normal prior art steering systems have brackets for coupling or attaching the rod to the transom, which brackets often have the serious drawback of not being adaptable to all commercially available watercrafts. Fastening arrangements for currently available cylinders also have the drawback of requiring totally different mounting methods, as the cylinder needs to be adapted by using shims depending on the type of motor being used. Unfortunately, this is a considerable problem, because each motor requires the length of the motor tube to be adjusted to the length between the mounting brackets. The problem is that mounting instructions shall be given for each motor (number, positioning and thickness of shim washers), thereby increasing mounting costs. Further, upon insertion of these shim washers, the small clearance that still exists is compensated for by using a ring nut and secured by a dowel. Therefore, apparent dowel access problems arise, as well as the expected ring nut loosening problems associated thereto.